Thread: Laying overlay flooring - Revisited

Hi all,

I found this old thread and thought "great!", but then noticed it has no replies at all and I was not able to submit my post to it!! (too old and I am totally inexperienced with using this forum) .

So, I'm going to revive this thread and ask for help!!
This is what the OP wrote:

I have 250m2 of 105 x 12mm overlay flooring arriving soon and am after advice on the best way to lay it. I have a good yellow tongue base. The place I'm getting the flooring from recommended full trowel gluing, with Bostik Ultraset Brown and no nailing ( I found some information on boral website for their overlay flooring which suggested the same). In the mean time I have bought a secret nailer thinking that I should glue and nail the boards.
I guess my question is if there is any benefit in nailing the boards as well as gluing or would it be a waste of effort. (... gluing just doesn't seem blokey enough!).
Thanks
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And this is our situation and my other questions:
We are thinking of installing 80-85mm wide overlay.

Should it always be installed over plywood and how thick? (It's a new slab downstairs).
Should we also put some plywood upstairs, on top of the existing standard builders particleboard? And how thick?
If we install 19mm thick sold floor upstairs, should it go over plywood as well?

Which timber is best suited for use as overlay floors? Is one specie better than another, perhaps it splits less and gets less damaged during the installation (I believe that overlay flooring has thinner t&g area and it could split easier)? Is tallowwood or brushbox or spotted gum still OK to use as overlay?

Is it possible to avoid craeting gaps between the boards during installation of overlay (or even 19mm boards)? I heard that many installers don't tighten the boards together at all, which then creates gaps right from start, and then they just fill them with putty before sanding. Is that OK? Or, can overlay floors be clamped and tightened together during installation - are they too delicate for that!??! Does it depend on specific species too??


Can new floors be finished with water based finishes (we're thinking Bona Traffic)? Would it edge bond the new floor??

Is it silly (or impossible) to install some kind of foam or rubber / cork underlay under the boards with the sole purpose of "softening" the feel when walking on the floors? If this is doable, what is the best underlay to use and best way to install it?

Any information would be greatly appreciated !!!
Thanks!